Investigation On Nanomaterials-Modified Electrochemical DNA And Aptamer Biosensor

The thesis developed new types of electrochemical DNA and aptamer biosensors determining thrombin and inorganic heavy metal ions Hg2+ and Pb2+, using DNA and aptamer as molecular recognition materials. The researches have certain significance in developing new DNA and aptamer biosensors as well as in enriching electroanalytical chemistry researches. There are three chapters in the thesis. The main studies are summarized as follows,1. A novel gold nanoparticles (Au NPs)-based electrochemical DNA biosensor for the detection of mercury (Ⅱ) ions (Hg2+) in aqueous solution was introduced in this article. The sensor can detect the Hg2+ concentration range of 1.0×10-9～1.0×10-6 mol·L-1, the detection limit of up to 5×10-10 mol·L-1. The DNA biosensor exhibits high sensitivity, good selectivity and no pollution.2. A novel MWCNTs-enhaced electrochemical aptamer biosensor detecting thrombin was introduced in this article, which was effective, sensitive, and had a sufficient specificity to the target. The current response of Fc was linearly related to thrombin concentration between 1.0×10-12 and 5.0×10-10 mol·L-1 with a detection limit of 5×10-13 mol·L-1. The aptasensor shows high specificity and good selectivity.3. An EMIMBF4-CeO2-MWCNTs nanocomposites amplified electrochemical aptamer biosensor detecting divalent lead ion (Pb2+) concentration was introduced in the article. The aptasensor can detect the Pb2+ concentration range of 1.0×10-8～1.0×10-5 mol·L-1, with a detection limit of 5×10-9 mol·L-1.